Process and catalyst for synthesizing aliphatic, cyclic and aromatic alkanolamines and alkyleneamines

ABSTRACT

The invention provides a process for synthesizing alkanolamines and/or alkyleneamines by reacting either an alkane, an alkene, or both with a source of oxygen and a source of nitrogen and, optionally, additional hydrogen to convert the alkane and/or alkene by selective partial oxidative amination to at least one of the desired end products. The invention further provides a regenerable catalyst for use in synthesizing alkanolamines and/or alkyleneamines by selective partial oxidative amination of alkanes and/or alkenes.

FIELD OF THE INVENTION

[0001] The present invention relates to the synthesis of aliphatic,cyclic and aromatic alkanolamines and alkyleneamines (collectivelyreferred to throughout the specification including the claims as“alkanolamines and alkyleneamines”) from alkanes and/or alkenes. Moreparticularly, the present invention provides a process for synthesizingalkanolamines and alkyleneamines by selective partial oxidativeamination of alkanes and/or alkenes. The invention further provides aregenerable catalyst which provides a favorable free energy for theselective partial oxidative amination reaction.

BACKGROUND OF THE INVENTION

[0002] Alkanolamines and alkyleneamines are currently manufactured usingalkylene oxides and ammonia as the key starting raw materials. Forexample, monoethanolamine, di- and tri-ethanolamine and ethylenediamineare currently manufactured using ethylene oxide and ammonia as thestarting raw materials. The manufacture of monoethanolamine requireshigh ammonia to ethylene oxide ratios in order to increase theselectivity to monoethanolamine. It is then necessary to refine andrecycle the excess ammonia which significantly increases the cost ofmonoethanolamine production. Once monoethanolamine is formed, it istreated with ammonia by a reductive amination process to produceethylenediamine and other higher acyclic and cyclic polyethyleneamines.Again, high ammonia ratios are employed to improve the selectivity tothe desired end product, typically, ethylenediamine.

[0003] Ethylene oxide is a relatively expensive compound, and the highcost of this material also unfavorably impacts the economics ofmonoethanolamine and ethylenediamine manufacture. In the case ofmonoethanolamine, for example, the raw materials may account for atleast 70% of the total monoethanolamine cost.

[0004] Another commercial process utilizes ethylene dichloride andammonia for the synthesis of ethylenediamine and other higher homologs.This process is energy intensive and requires expensive refiningequipment. Furthermore, the resultant hydrochloride salts of ammonia andthe polyethyleneamines must undergo neutralization with caustic (usuallysodium hydroxide) to give the free amine product. Separation of thepolyethyleneamines and the salt is difficult, and the byproduct saltmust be disposed of which further increases the cost of the process.

[0005] A process which could produce alkanolamines and alkyleneaminesfrom alkanes and/or alkenes as the starting hydrocarbon raw materialswould provide a desirable advantage over the current prior art. In thecase of monoethanolamine and ethylenediamine, for example, using ethaneand/or ethylene as the starting raw material(s) would providesignificantly improved variable costs compared to ethylene oxide andethylene dichloride. It would also avoid the need to handle ethyleneoxide—a highly reactive chemical.

[0006] The partial oxidative amination of alkanes and alkenes provides athermodynamically favorable route to alkanolamines and alkyleneamines,as demonstrated further below. The primary concern with respect to thepartial oxidative amination of alkanes and alkenes is selectivity, i.e.,the formation of desirable alkanolamines and alkyleneamines rather thanthe complete conversion of the starting materials to CO₂ and water. Inaddition, preventing or limiting the oxidation of ammonia and othernitrogen sources to NO_(x) type species and limiting NO_(x)/hydrocarbonreactions are other significant concerns.

[0007] A process that effectively addresses these concerns would achievea novel and practicable means of producing alkanolamines andalkyleneamines. Such an approach would also provide clear economicadvantages over the present method of synthesizing these materials fromethylene oxide or ethylene dichloride.

SUMMARY OF THE INVENTION

[0008] The present invention meets these objectives by providing, in oneaspect, a process for producing alkanolamines and/or alkyleneamines byreacting at least one of an alkane and an alkene with a source of oxygenand a source of nitrogen and, optionally, additional hydrogen to convertthe alkane and/or alkene by partial oxidative amination to at least oneof the desired end products.

[0009] Any source of nitrogen suitable for carrying out the reaction maybe utilized, such as ammonia, hydrazine, amines, nitrous oxide in thepresence of a reducing gas such as H₂, hydrocarbon, etc., and othernitrogen-containing compounds. In the case of monoalkanolamines andalkyleneamines, ammonia is preferred.

[0010] The necessary oxygen may be obtained from any suitable source,including without limitation, oxygen, ozone, oxides of nitrogen, water,and alcohols. Preferably, oxygen is used to carry out the reaction. TheO₂ may be fed at any concentration by mixing with N₂, He, or other inertgases. A convenient and safe source of oxygen is air. The requiredoxygen may also be provided by a suitable metal oxide catalyst or by thereaction of a metal oxide catalyst with N₂O, NO_(x) or sulfur oxideswhich may be generated in situ or supplied to the reaction systemindirectly. In a preferred embodiment of the invention, the oxygen issupplied by one or more reducible metal oxide catalysts that areregenerated by exposure to air, O₂, other oxygen containing gases, orother suitable oxygen sources.

[0011] Sufficient hydrogen for the reaction is typically provided by theammonia or amine utilized as the nitrogen source, by the alkane and/oralkene raw materials, or by hydroxyl groups present on the surface ofthe catalyst. However, in the event these sources do not containsufficient hydrogen, an additional source of hydrogen may be directly orindirectly provided, for example, H₂ gas. The necessary hydrogen mayalso be provided by one or more hydrogenation/dehydrogenation metalcatalysts.

[0012] In a second aspect, the invention relates to a metal or metaloxide catalyst which provides a favorable standard free energy for thepartial oxidative amination reaction.

[0013] Reducible metal oxide catalysts have been found to beparticularly suitable for synthesizing alkanolamines and alkaneneaminesby partial oxidative amination. These types of metal oxides (referred toherein as “red-ox” catalysts) allow for the ready accessibility oflattice oxygen to promote the oxidation of the feed materials, whichresults in a corresponding reduction of the metal oxide. This isfollowed by re-oxidation of the catalyst by another oxygen source, suchas O₂ or an oxygen-containing gas. Examples of effective red-oxcatalysts include, but are not limited to, the oxides of cerium, iron,copper, nickel, lead, cadmium, molybdenum, vanadium, bismuth, manganese,barium, cobalt, strontium, tungsten, samarium, osmium, rhenium, rareearth elements, and mixtures of these oxides.

[0014] Those metals which are generally known ashydrogenation/dehydrogenation metals are also effective for carrying outthe reaction, either alone or in combination with above-mentioned metaloxide catalysts. As explained in more detail below, it is believed thatthese catalysts generate highly reactive hydroperoxo and/or peroxospecies from O₂ and H₂ and provide the oxygen and hydrogen necessary forthe oxidative amination reaction. These catalysts include but are notlimited to nickel, palladium, platinum, cobalt, rhodium, iridium, iron,ruthenium, copper, zinc, gold, silver and mixtures of these metals.

[0015] Typically, both the red-ox and hydrogenation/dehydrogenationcatalysts are supported on suitable carriers such as cerias, titanias,zirconias, silicas, aluminas, ∝-alumina, silicon carbide, aluminumphosphate molecular sieves (AlPO's), high silica molecular sievezeolites, MCM-type large pore zeolites, mixtures of these carriers, andother catalyst support materials well-known in the art.

BRIEF DESCRIPTION OF THE FIGURES

[0016]FIG. 1 contains a series of plots illustrating the standard freeenergy change as a function of temperature for a number of ethylenebased routes to monoethanolamine.

[0017]FIG. 2 contains a series of plots illustrating the standard freeenergy change as a function of temperature for a number of ethane basedroutes to monoethanolamine.

[0018]FIG. 3 contains a series of plots illustrating the standard freeenergy change as a function of temperature for a number of ethylenebased routes to ethylenediamine.

[0019]FIG. 4 contains a series of plots illustrating the standard freeenergy change as a function of temperature for a number of ethane basedroutes to ethylenediamine.

[0020]FIG. 5 is schematic illustration of a circulating fluidized bedreactor for carrying out the process of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention will be described in connection with anexplanation of the synthesis of monoethanolamine and ethylenediaminefrom ethane and/or ethylene. However, as will be apparent to thoseskilled in the art, the invention may be used to synthesize otheralkanolamines and alkyleneamines depending on the particular alkanesand/or alkenes selected as the hydrocarbon starting materials and thechoice of raw material feeds

[0022] Three routes to monoethanolamine based on selective partialoxidative amination of ethylene and ethane, respectively, are set forthbelow:

CH₂═CH₂+½O₂+NH₃→HOCH₂—CH₂NH₂  (1)

CH₃—CH₃+O₂+NH₃→HOCH₂—CH₂NH₂+H₂O  (2)

CH₂═CH₂+O₂+H₂+NH₃→HOCH₂—CH₂NH₂+H₂O  (3)

[0023] The reactions may be carried out in gas, liquid, supercritical,or multiphase media. As noted previously, any suitable source of oxygen,nitrogen, and hydrogen may be utilized to convert ethylene and/or ethaneto monoethanolamine. However, when the reactions are carried out in thevapor phase, oxygen and ammonia are the preferred forms of thesereactants. As to the hydrocarbon raw materials, it should also beunderstood that the use of ethylene and ethane are not mutuallyexclusive, and that a mixture of these reactants may be utilized in thesynthesis of monoethanolamine.

[0024] The reactions may be carried out over a broad range oftemperatures and pressures. Generally, however, conditions of relativelylow temperature and relatively high pressure are preferred. Lowertemperatures tend to enhance selectivity and reduce or eliminate theformation of undesirable NO_(x) by-products. Higher pressures generallyincrease the rate at which the desired end products are formed.Typically, the synthesis is carried out at temperatures ranging fromabout 25° C. to about 500° C. and at pressures ranging from about 1atmosphere to about 200 atmospheres.

[0025] While not intending to be limited to a particular theory ormechanistic pathway, the partial oxidative amination represented inreaction (1) and (2) proceeds, as presently understood, by the formationof one or both of the following intermediates:

[0026] In the most preferred embodiment of the invention, reactions (1)and (2) proceed over a reducible and regenerable metal oxide red-oxcatalyst. Generally, metal oxides suitable for use in the invention arethose metal oxides that are reduced by reaction with a hydrocarbonmoiety to a lower oxidative state, such that the metal oxide provides alower standard free energy for the partial oxidative amination reaction,in this particular case the reaction to produce monoethanolamine. Oxygenfrom the feed material then re-oxidizes the metal oxide. For thesynthesis of monoethanolamine from ethylene and ethane, respectively,exemplary reactions are shown as follows:

[0027] For other metal oxides, similar red-ox reactions can be depictedas shown above by balancing the appropriate valences and coefficientsfor the particular metal oxide selected.

[0028] It is believed that the necessary,oxygen is provided by thesecatalysts as oxygen which moves from the lattice to the surface (perhapsas O⁻², O⁻, or O₂ ⁻ surface species). One possibility that may accountfor the high activity of these catalysts is that the metal oxides havepoint defects, step defects, other types of defects or disorders, orcation vacancies within the lattice which provides for the readyaccessibility of oxygen. Whatever the basis for their highly activenature, a number of metal oxides are particularly suitable for carryingout the selective partial oxidative amination of alkanes and alkenesincluding NiO, PbO, CdO, MoO₃, V₂O₄, V₂O₅, BiO, Bi₂O₃, CuO, CU₂O, MnO₂,Mn₂O₃, Mn₃O₄ BaO₂, Co₃O₄, SrO₂, WO₂, WO₃, SnO₂, CeO₂, OsO₄, Re₂O₇,Fe₂O₃, Fe₃O₄, rare earth oxides, and mixtures of these metal oxides.

[0029] The partial oxidative amination represented in reaction (3) isbelieved to proceed by the formation of hydroperoxo and peroxointermediates having the following structure:

[0030] These intermediates are formed by reaction of ahydrogenation/dehydrogenation metal catalyst with O₂ and then byreaction with H₂. The oxygen adsorbed on the catalyst, either as thehydroperoxo or peroxo intermediate, is capable of adding to an olefinwhich has been added either as a feed material, or generated in situ byoxidation of an alkane or alkene. The intermediate generated fromreaction of the oxygen with the olefin is an epoxide. The epoxide thenreacts with the nitrogen compound to give the end product. For example,a feed of ethylene and/or ethane with ammonia would produce ethyleneoxide as an intermediate which would react with the ammonia to producemonoethanolamine. Monoethanolamine can also react with the ethyleneoxide to give diethanolamine as a product. Typically, reactionconditions are controlled to give the desired end product. Thosehydrogenation/dehydrogenation metals that are the most active include,but are not limited to, nickel, palladium, platinum, cobalt, rhodium,iridium, iron, ruthenium, copper, zinc, gold, and silver and mixtures ofthese metals.

[0031] The red-ox and hydrogenation/dehydrogenation catalysts describedherein can be prepared by conventional procedures known in the art. Forexample, the catalyst can be incorporated on preformed carriers orsupports (these terms are used interchangeably herein) by impregnatingthe carrier with a liquid solution comprising a form of the elementrequired to effect reaction. The support shape is generally not narrowlycritical; accordingly, the carrier may take the form of, for example,pellets, extruded particles, spheres, rings, monoliths and the like. Ifmore than one metal is to be incorporated the metals may be incorporatedsimultaneously or sequentially, the sequence of which is not narrowlycritical. As noted above, typical supports include cerias, titanias,zirconias, silicas, aluminas, ∝-alumina, silicon carbide, aluminumphosphate molecular sieves (AlPO's), high silica molecular sievezeolites, MCM-type large pore zeolites, mixtures of these carriers, andother catalyst support materials well-known in the art.

[0032] Generally, the metal is in the form of a salt which can be easilydissolved in a liquid solvent for incorporation into the particles ormonolith structure of the carrier. Several impregnation steps may berequired depending on the amount of metal or metal oxide required andthe solubility of the salt of the catalytic compound in the solvent. Adrying step is generally employed between each impregnation. This is awell known procedure in the art for incorporating metals and metaloxides onto a solid support material. After all of the impregnationsteps are completed, the material is then usually heated at highertemperatures, typically from 100-900° C., to effect at least partialdecomposition of the salt to the metal oxide. Alternatively, the metalsalt may be heated to 100-900° C. after each impregnation and dryingstep. The drying and heating steps may be done incrementally at varioustemperatures over suitable periods of time, or these steps can be rampedup to the desired temperature fairly linearly. If desired, the metaloxide can be reduced to the metal, at least partially, with hydrogen orother reducing gases (e.g. carbon monoxide) using methods well known toone skilled in the art.

[0033] Alternatively, some form of the requisite metal can be fused,bonded or compressed into solid pellets or larger structures, orcomposited with one or more support materials, in association with oneor more metal oxides and heated as above. The material may be reduced asalluded to above.

[0034] Still further, the catalyst can be provided at the time ofpreparing the support material. For example, one or more metal oxidesmay be condensed from their respective hydrolyzable monomers to thedesired oxides to form oxide powders which can thereafter be blended andcompressed to form pellets and larger structures of the catalyst. Thematerials are then heated and optionally reduced as alluded to above.

[0035] In yet another approach, the metal salt may be precipitated on apreformed carrier using methods described in the art. This procedureoffers some advantages for depositing the active metal on the outside ofthe carrier which may lead to improved selectivity. Some furtheradvantages may be realized by preparing the partial oxidative aminationcatalyst on zeolite-type materials. For zeolites, known ion-exchangeprocedures may be employed to incorporate various catalytic metal ions.This allows for shape selectivity and can enhance partial oxidativeamination over complete oxidation. The procedures for incorporatingmetals on zeolites are well known.

[0036] The use of supports for the catalysts provides a number ofsignificant advantages. Some of the catalysts are not structurallystable under the reaction conditions when utilized over an extendedperiod of time. In a batch reaction this is not a significant issue.However, when the reaction is effected with the catalyst as part of afixed bed reactor, in a tubular reactor, or in a fluid bed reactor it isdesirable that the catalyst have greater structural stability/integrityfor the reaction medium.

[0037] Attrition can be a significant problem with an unsupportedcatalyst particularly if used in a fluidized bed reactor. Improvedresistance to attrition of the catalyst can be achieved by providing anattrition resistant coating on the surface of the catalyst. The coatingshould be resistant to the reactants and products and must besufficiently porous to permit free passage of the reactants and productsthrough the coating to the catalyst site. Polysilicic acid, zinc oxide,titanium oxide, zirconium oxide, other metal oxides and mixtures ofthese oxides may be used to provide an outer coating on the catalystwhich provides better attrition resistance. The techniques used toprovide a protective coating are well known to one skilled in the art.

[0038] In one embodiment of the invention, the reducible metal oxidecatalyst has a microstructure characterized by a plurality of porousmicrospheres. An attrition resistant coating is provided on the surfaceof the microspheres. In this particular example, the coating comprisespolysilicic acid. However, as mentioned above the coating may be formedfrom other inert materials that will also provide attrition resistance,such as zinc oxide, TiO₂, ZrO₂ and other metal oxides.

[0039] Referring now to the synthesis of ethylenediamine, the conversionof ethylene and ethane, respectively, to form ethylenediamine isrepresented by the following reactions:

CH₂═CH₂+½O₂+2NH₃→H₂NCH₂CH₂NH₂+H₂O  (6)

CH₃—CH₃+O₂+2NH₃→H₂NCH₂CH₂NH₂+2H₂O  (7)

[0040] The following illustrates an optimal reaction for formingethylenediamine by means of hydroperoxo and/or peroxo intermediates:

CH₂═CH₂+½O₂+H₂+2NH₃→H₂NCH₂CH₂NH₂+H₂O  (8)

[0041] The partial oxidative amination of ethane and/or ethylene toethylenediamine proceeds under essentially the same reaction conditionsand in essentially the same manner as that described above in connectionwith the synthesis of monoethanolamine. Accordingly, the reactions maybe carried out in gas, liquid, supercritical or multiphase media.Various sources of oxygen and nitrogen may be utilized to convertethylene and ethane to ethylenediamine; however, oxygen gas, preferablymixed with an inert gas, and ammonia are preferred. Either ethylene orethane may be used as the starting hydrocarbon raw material for thesynthesis of ethylenediamine, or, a mixture of these starting materialsmay be employed. The partial oxidative amination reactions may becarried out over a broad range of temperatures and pressures. Generally,however, the same conditions of relatively low temperature andrelatively high pressure discussed above in connection with thesynthesis of monoethanolamine are preferred. Thus, the synthesis ofethylenediamine is typically carried out at temperatures ranging fromabout 25° C. to about 500° C. and at pressures ranging from about 1atmosphere to about 200 atmospheres.

[0042] As in the case of monoethanolamine, the partial oxidativeamination of ethane and/or ethylene to produce ethylenediamine ispreferably carried out over a reducible metal oxide catalyst whichprovides the oxygen necessary for the reaction. The metal oxidessuitable for synthesizing ethylenediamine are the same catalystsdescribed above in connection with the synthesis of monoethanolamine.

[0043] In a preferred embodiment of the invention, the catalyst iscontinuously regenerated and recycled as illustrated in reaction (9) and(10):

[0044] For other metal oxides, similar red-ox reactions can be depictedas shown above by balancing the appropriate valences and coefficientsfor the particular metal oxide selected.

[0045] FIGS. 1-4, illustrate that there are no thermodynamic barriers tothe conversion of ethane and ethylene to monoethanolamine andethylenediamine by partial oxidative amination. The non-catalyzedreaction which utilizes oxygen gas as the source of the required oxygenexhibits a highly favorable standard free energy change in all cases.Somewhat less favorable, but still thermodynamically advantageous freeenergy changes are provided by the use of a suitable metal oxidecatalyst or a hydrogenation/dehydrogenation metal catalyst. The chiefadvantages provided by the use of these catalysts are enhancedselectivity and increased conversion of the hydrocarbon startingmaterials to monoethanolamine and ethylenediamine. At the same time, thegenerally lower reaction temperatures at which highly active catalystsoperate tend to minimize or eliminate the formation of NO_(x) byproducts. For example, FIGS. 1-4 illustrate that a reducible MnO₂catalyst provides a very favorable standard free energy change at atemperature of about 250° K. (−23.6° C.) for the partial oxidativeamination of both ethylene and ethane to either monoethanolamine orethylenediamine.

[0046] The reaction may be effected by the incremental addition of oneof the reactants to the other or by the joint addition of the reactantsto the catalyst. The reaction may be carried out by slurrying thecatalyst in the reactants (optionally in a solvent) or in a batch orsemi-batch mode in an autoclave. Solvents may be used to provide twoliquid phases one of which contains the partial oxidative aminationcatalyst and the other the reactants with a sufficient amount of mixingto effect reaction. A more preferred process effects the reaction in acontinuous manner over a fixed bed or fluidized bed of the partialoxidative amination catalyst in a tubular reactor.

[0047] Inorganic membrane reactors may be used to control theconcentration of reactants (e.g., oxygen) in the partial oxidativeamination catalyst bed, and/or to provide a source of the partialoxidative amination catalyst. The reactor may be an inert membranepacked bed reactor (IMPBR), an inert membrane fluidized bed reactor(IMFBR), a catalytic membrane reactor (CMR), a packed bed catalyticmembrane reactor (PBCMR), or a fluidized bed catalytic membrane reactor(FBCMR).

[0048] In a preferred embodiment, the reaction is carried out in acirculating fluidized bed reactor. Such a reactor is shown schematicallyin FIG. 5. The reactor, generally designated 100, which includes a riser102, a separator/stripper 104, a connecting conduit or pipe 106, aregenerator 108 and a stand pipe 110 arranged in a loop around which thesolid metal oxide catalyst is continuously circulated. The processcarried out by the reactor will be explained in the context of thepartial oxidative amination of ethylene to monoethanolamine asillustrated in reaction (4), although it should be understood thatessentially the same process has general applicability for the partialoxidative amination of alkanes and/or alkenes to alkanolamines and/oralkyleneamines.

[0049] The metal oxide catalyst particles are carried upward in theriser 102 by a stream of high velocity gas containing ethylene andammonia. The ethylene undergoes partial oxidative amination in the riserand the metal oxide catalyst is converted to its reduced form asillustrated on the right in reactions (4), (5), (9) and (10). Thereduced catalyst particles are then separated from the product streamand stripped of any carbonaceous species in the separator/stripper 104and then passed through the connecting conduit 106 to the regenerator108. There, the reduced catalyst is reoxidized by exposure to air orsome other suitable oxygen-containing gas stream. The reoxidizedcatalyst is then directed back into the bottom of the riser by the standpipe 110.

[0050] The use of a circulating fluidized bed reactor provides a numberof advantages. The essentially plug flow characteristics of gas andcatalyst particles in the riser give high selectivity tomonoethanolamine, and the absence of oxygen gas in the riser furtherimproves selectivity by reducing monoethanolamine destruction or theundesirable formation of nitrogen oxides. Loosely bound highly activeoxygen species are eliminated prior to entry into the riser whichresults in increased conversion and the maintenance of high catalystselectivity. The high circulation rate of the catalyst also provides aheat sink which helps control the temperature in the riser and reducesthe heat transfer area that would otherwise be required to remove theheat of reaction. Accordingly, the reactor design provides economic aswell as process advantages.

[0051] While the use of a circulating fluid bed reactor providesimportant advantages, it should be understood that the invention is notlimited in this regard. It should also be understood that regardless ofwhich type of reactor is utilized, should the metal oxide catalyst notprovide sufficient oxygen small amounts of additional O₂ may be bleedinto the reaction system. Typically, if additional oxygen is required itis added in an amount less than about 5%, and preferably less than about2%, based on the total feed.

[0052] As noted previously, the present invention has been described indetail in the context of producing monoethanolamine and ethylenediamineby the partial oxidative amination of ethylene and/or ethane. However,those skilled in the art will readily appreciate that the invention hasgeneral application for the production of other alkanolamines andalkyleneamines from a variety of alkane and alkene starting materials.For example, propanolamines and diaminopropanes can be formed by thepartial oxidative amination of propylene and propane according toessentially the same manner as illustrated in reactions (1) -(9). Thisis equally true for higher homologs of ethane and ethylene and theirassociated alkanolamines and alkyleneamines.

[0053] Diethanolamine and triethanolamine may also be formed based onthe partial oxidative amination of ethane and/or ethylene. In the caseof diethanolamine, for example, once monoethanolamine is produced by oneor more of the mechanisms illustrated by reactions 1-5, additionalethane and/or ethylene is reacted with monoethanolamine as set forth inreaction (11) to form the desired end product: (11)

[0054] As will be appreciated by those skilled in the art, if additionalethane and/or ethylene is provided, the reaction will proceed to theformation of triethanolamine.

[0055] Those skilled in the art will also readily appreciate that thereactions described above are not mutually exclusive. That is, eithermonoethanolamine or ethylenediamine may be produced, or both of theseproducts may be produced simultaneously. The particular product(s)produced and the particular route(s) by which this is accomplished aredetermined by controlling the partial pressure of the hydrocarbon rawmaterials and the partial pressure of the ammonia and the choice of asuitable catalyst.

[0056] Accordingly, the present invention provides a practicable andeconomic means of producing a wide variety of alkanolamines andalkyleneamines based on the use of alkanes and/or alkenes as thehydrocarbon starting materials. Although specific embodimentsillustrating the invention have been disclosed, it should be understoodthat the invention has been described by way of example and not bylimitation.

1. A process for synthesizing at least one of an alkanolamine and analkyleneamine, said process including the step of: reacting an alkaneand/or an alkene with a source of oxygen, a source of nitrogen and,optionally, additional hydrogen to convert said alkane and/or alkene bypartial oxidative amination to at least one of said alkanolamine andalkyleneamine.
 2. The process of claim 1 , wherein the source ofnitrogen is at least one of ammonia, hydrazine, amines, and nitrousoxide in the presence of a reducing gas.
 3. The process of claim 1 ,wherein the source of oxygen is at least one of oxygen, ozone, oxides ofnitrogen, water, and alcohols.
 4. The process of claim 1 , wherein theoxygen is provided by at least one metal oxide catalyst.
 5. The processof claim 4 , wherein the metal oxide catalyst comprises at least onemetal oxide that is reduced by reaction with a hydrocarbon moiety to alower oxidation state such that the metal oxide provides a lowerstandard free energy for the partial oxidative amination of the alkaneand/or alkene.
 6. The process of claim 4 , wherein the catalyst isregenerable.
 7. The process of claim 4 , wherein the alkane and/oralkene is reacted with the source of nitrogen over the catalyst in acirculating fluidized bed reactor.
 8. The process of claim 6 , whereinthe metal oxide catalyst is regenerated by exposing the catalyst to asource of oxygen.
 9. The process of claim 1 , wherein ethane and/orethylene is reacted with ammonia and oxygen to form at least one ofmonoethanolamine and ethylenediamine.
 10. The process of claim 2 ,wherein the ammonia is provided at a partial pressure which determinesthe ratio of alkanolamine and alkyleneamine synthesized.
 11. The processof claim 1 , wherein in addition to a source of nitrogen and a source ofoxygen the alkane and/or alkene is reacted with a source of hydrogen.12. The process of claim 11 , wherein a hydrogenation/dehydrogenationcatalyst is present with the source of hydrogen.
 13. The process ofclaim 1 , wherein the reaction is carried out in one of gas, liquid,multi-phase, and super critical media.
 14. The process of claim 9 ,wherein the alkanolamine is monoethanolamine which is reacted further toform at least one of diethanolamine and triethanolamine.
 15. Aregenerable catalyst for use in synthesizing at least one of analkanolamine and/or alkyleneamine by partial oxidative amination ofalkanes and/or alkenes, said catalyst comprising at least one of: areducible metal oxide that is reduced by reaction with a hydrocarbonmoiety to a lower oxidative state, such that the metal oxide provides alower standard free energy for the partial oxidative amination ofalkanes and alkenes: and a hydrogenation/dehydrogenation metal capableof generating at least one of a hydroperoxo and peroxo intermediate. 16.The catalyst of claim 15 , wherein the reducible metal oxide is selectedfrom the group consisting of oxides of cerium, iron, copper, nickel,lead, cadmium, molybdenum, vanadium, bismuth, manganese, barium, cobalt,strontium, tungsten, samarium, osmium, rhenium, rare earth elements, andmixtures of these oxides.
 17. The catalyst of claim 16 , wherein themetal oxided is selected from the group consisting of: NiO, PbO, CdO,MoO₃, V₂O₄, V₂O₅, BiO, Bi₂O₃, CuO, Cu₂0, MnO₂, Mn₂O₃, Mn₃O₄ BaO2,Co₃O₄SrO₂, WO₂, WO₃, SnO2, CeO₂, OsO₄, Re₂O₇, Fe₂O₃, Fe₃O₄, rare earthoxides, and mixtures thereof.
 18. The catalyst of claim 15 , wherein thehydrogenation/dehydrogenation metal is selected from the groupconsisting of: nickel, palladium, platinum, cobalt, rhodium, iridium,iron, ruthenium, copper, zinc, gold, and silver and mixtures thereof.19. The catalyst of claim 15 further comprising a carrier for supportingat least one of the reducible metal oxide and thehydrogenation/dehydrogenation metal.
 20. The catalyst of claim 19 ,wherein the carrier is selected from the group consisting of: cerias,titanias, zirconias, silicas, aluminas, ∝-alumina, silicon carbide,aluminum phosphate molecular sieves (AlPO's), high silica molecularsieve zeolites, MCM-type large pore zeolites, mixtures thereof.